Learning my new-to-me-diesel fellas. The '97 PSD owner's guide supplement says "The WATER IN FUEL light will glow when the fuel filter/water separator has a significant quantity of water, or when the ignition key is switched to the START position (light function check).

In threads on this site, guys who seem to know what they are talking about clearly state there is no function check for the WATER IN FUEL light. What's the story with this?

Speaking of warnings and indicators, if my 4x4 and low range indicator lights don't function, should I start with the bulbs or wiring/connectors at the transfer case? Is this common? Thanks.

Mike

 

I dont think there is any function check on that at all. The best way I have found to notice H2O in the filter bowl is when making turns, It it flickers on then you have a early sign of water. Find some weeds to water and I like to do it with the motor running, that is if I have not been hauling for a long while. If I haul I let her idle down and cool off before dumping.
-- Dont have a good answer on the 4x4 light. Have you been whiching when its on flat ground and in neutral?

 

There is a sensor (that often leaks) on the side of the fuel bowl. Its function is to turn the light in the dash on if water reaches that level. If you drain the bowl and change your fuel filter regularly I doubt it would ever come on. If the light doesn't come on when you start the truck that might be a concern. I haven't have it come on in 23 years of diesels.

 

When you flip the drain switch does it only dump the water? Or fuel also? And is it best to have it running or not?

Also where does it drain to???

 

Dumps whatever is in the canister. Not running. Look up under the front of the engine where the CPS is. It's a 5/16" pipe sticking down toward the passenger side. I use a 3/8" thin wall hose to drain into a container. Kind hard to find the first time you look for it.

 

Ok. Thanks.

 

as for the water in fuel, i thought that was more a winter time problem with more ethanol in the fuel? i thought by now all stations would have lower ethanol content thus not creating water. or am i just an idiot and the water comes in from some form of magic trickery!!!

 

ethanol.....that's blended into gasoline

The water in the fuel comes from water in the storage tanks, either from condensation or ground water seeping in thru leaky underground tanks.

 

Looked and looked for that darn pipe from below until finally I'd had enough. Put a 16" long by 10" wide clear plastic container under the oil pan and opened the valve. Diesel sprayed out pretty good...but at least now I could follow the drips!

Closed the valve and discovered the 5/16" metal tube terminates about 1 inch right above a major (at least 1/2" thick) ground wire, probably for the starter. This causes the fuel to spray everywhere. Now I know where to attach some thin fuel line next time for proper discharge into a container.

Been doing lots of reading about diesels and have talked to a technician at Diesel Injection Service here in Madison, Wis. According to these guys, water is a constant threat to the fuel system. They recommend regular attention to filters, continuous use of an additive that helps separate water out of the fuel, and regular purging of the filter canister.

My buddy brought this to my attention after he had to have all his injectors replaced on his 2003 F250 Super Duty with 130K miles.... $3700 dollars later he was as good as new. He's also now using the recommended additive.

Still want to know if any of you guys have a truck where the WATER IN FUEL light comes on when the key is moved forward to the "ON" position like it says in my Ford owner's manual. Mine does not.

Engine temp and fuel filter lights cycle on as truck starts... but nothing from the WATER IN FUEL light! Thanks.
Mike

 

I keep that 5/16" line attached to the drain line 24-7, in fact it hangs down past the tie rod so when I get ready to do a drain I can slip it into a plastic water bottle and the bottle won't fall over and I can see just how much water I had if any.

Rog

 

I've never had the water in fuel light come on...

 

I saw the message you left for me. Mine indeed does come on during cranking, even though the shop manual doesn't show a connection for the light.

As for draining:

Mine didn't drain well before I rebuilt the fuel system with new hoses and O-rings. There are two valves on the water separator. The upper one lets air into the separator through a little hole and the lower one drains it. When I took things apart, the little hole was plugged with sludge. It would only drain when the engine was running.

Now with the hole open, it drains freely with the engine off.

I have found that I can take an old quart oil bottle and wedge it in under the drain before I open the valve.

 

Thanks for your reply Joe. Armed with your information (the light should come on with the key function check), I will tear into the filter canister and look for the problem with my WATER IN FUEL warning indicator. I've already had the dash apart and verified the fuction of the bulb with a 12-volt power supply. Since its not the bulb, something else must be boogered up. I sincerely appreciate your reply and your time.

 

Your bulb must be burned out. It's supposed to come on during the crank cycle in order to check the the bulb. Mine has been burned out since...well, forever. I replace the filter every oil change, 5-7K miles. I have a long hose permanently attached to the drain tube so it can be caught in a mason jar setting on the ground. I have not see water in the fuel...yet.

 

Mike, when cranking the engine the "engine temp", "water in fuel" and "fuel filter" lights should come on. Do all three do that?

Next is the "water in fuel" sensor is located in the fuel filter. It is a simple sensor and the actual switch module is a solid state device with a four wire connection located in front of the fuel filter canister.

Here is what is looks like on my 97 ...